lucene-java-3.5.0/lucene/contrib/xml-query-parser/src/demo/java/org/apache/lucene/xmlparser/webdemo/FormBasedXmlQueryDemo.java

   1 /**
   2  * Licensed to the Apache Software Foundation (ASF) under one or more
   3  * contributor license agreements.  See the NOTICE file distributed with
   4  * this work for additional information regarding copyright ownership.
   5  * The ASF licenses this file to You under the Apache License, Version 2.0
   6  * (the "License"); you may not use this file except in compliance with
   7  * the License.  You may obtain a copy of the License at
   8  *
   9  *     http://www.apache.org/licenses/LICENSE-2.0
  10  *
  11  * Unless required by applicable law or agreed to in writing, software
  12  * distributed under the License is distributed on an "AS IS" BASIS,
  13  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  14  * See the License for the specific language governing permissions and
  15  * limitations under the License.
  16  */
  17
  18 package org.apache.lucene.xmlparser.webdemo;
  19
  20 import java.io.BufferedReader;
  21 import java.io.IOException;
  22 import java.io.InputStream;
  23 import java.io.InputStreamReader;
  24 import java.util.Enumeration;
  25 import java.util.Properties;
  26 import java.util.StringTokenizer;
  27
  28 import javax.servlet.RequestDispatcher;
  29 import javax.servlet.ServletConfig;
  30 import javax.servlet.ServletException;
  31 import javax.servlet.http.HttpServlet;
  32 import javax.servlet.http.HttpServletRequest;
  33 import javax.servlet.http.HttpServletResponse;
  34
  35 import org.apache.lucene.analysis.Analyzer;
  36 import org.apache.lucene.analysis.standard.StandardAnalyzer;
  37 import org.apache.lucene.document.Document;
  38 import org.apache.lucene.document.Field;
  39 import org.apache.lucene.index.CorruptIndexException;
  40 import org.apache.lucene.index.IndexWriter;
  41 import org.apache.lucene.search.IndexSearcher;
  42 import org.apache.lucene.search.Query;
  43 import org.apache.lucene.search.ScoreDoc;
  44 import org.apache.lucene.search.TopDocs;
  45 import org.apache.lucene.store.RAMDirectory;
  46 import org.apache.lucene.xmlparser.CorePlusExtensionsParser;
  47 import org.apache.lucene.xmlparser.QueryTemplateManager;
  48
  49 public class FormBasedXmlQueryDemo extends HttpServlet {
  50
  51         private QueryTemplateManager queryTemplateManager;
  52         private CorePlusExtensionsParser xmlParser;
  53         private IndexSearcher searcher;
  54         private Analyzer analyzer=new StandardAnalyzer(org.apache.lucene.util.Version.LUCENE_CURRENT);
  55
  56         @Override
  57         public void init(ServletConfig config) throws ServletException {
  58                 super.init(config);
  59                 try {
  60                         openExampleIndex();
  61
  62                         //load servlet configuration settings
  63                         String xslFile=config.getInitParameter("xslFile");
  64                         String defaultStandardQueryParserField = config.getInitParameter("defaultStandardQueryParserField");
  65
  66
  67                         //Load and cache choice of XSL query template using QueryTemplateManager
  68                         queryTemplateManager=new QueryTemplateManager(
  69                                         getServletContext().getResourceAsStream("/WEB-INF/"+xslFile));
  70
  71                         //initialize an XML Query Parser for use by all threads
  72                         xmlParser=new CorePlusExtensionsParser(defaultStandardQueryParserField,analyzer);
  73                 } catch (Exception e) {
  74                         throw new ServletException("Error loading query template",e);
  75                 }
  76         }
  77
  78         @Override
  79         protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  80                 //Take all completed form fields and add to a Properties object
  81                 Properties completedFormFields=new Properties();
  82                 Enumeration pNames = request.getParameterNames();
  83                 while(pNames.hasMoreElements()){
  84                         String propName=(String) pNames.nextElement();
  85                         String value=request.getParameter(propName);
  86                         if((value!=null)&&(value.trim().length()>0)){
  87                                 completedFormFields.setProperty(propName, value);
  88                         }
  89                 }
  90
  91                 try{
  92
  93                         //Create an XML query by populating template with given user criteria
  94                         org.w3c.dom.Document xmlQuery=queryTemplateManager.getQueryAsDOM(completedFormFields);
  95
  96                         //Parse the XML to produce a Lucene query
  97                         Query query=xmlParser.getQuery(xmlQuery.getDocumentElement());
  98
  99                         //Run the query
 100                         TopDocs topDocs = searcher.search(query,10);
 101
 102                         //and package the results and forward to JSP
 103                         if(topDocs!=null)       {
 104                                 ScoreDoc[] sd = topDocs.scoreDocs;
 105                                 Document[] results=new Document[sd.length];
 106                                 for (int i = 0; i < results.length; i++) {
 107                                         results[i]=searcher.doc(sd[i].doc);
 108                                         request.setAttribute("results", results);
 109                                 }
 110                         }
 111                         RequestDispatcher dispatcher = getServletContext().getRequestDispatcher("/index.jsp");
 112                         dispatcher.forward(request,response);
 113                 }
 114                 catch(Exception e){
 115                         throw new ServletException("Error processing query",e);
 116                 }
 117         }
 118
 119         private void openExampleIndex() throws CorruptIndexException, IOException {
 120
 121                 //Create a RAM-based index from our test data file
 122                 RAMDirectory rd=new RAMDirectory();
 123                 IndexWriter writer=new IndexWriter (rd,analyzer,IndexWriter.MaxFieldLength.LIMITED);
 124                 InputStream dataIn=getServletContext().getResourceAsStream("/WEB-INF/data.tsv");
 125                 BufferedReader br = new BufferedReader(new InputStreamReader(dataIn));
 126                 String line = br.readLine();
 127                 while(line!=null)
 128                 {
 129                         line=line.trim();
 130                         if(line.length()>0)
 131                         {
 132                                 //parse row and create a document
 133                                 StringTokenizer st=new StringTokenizer(line,"\t");
 134                                 Document doc=new Document();
 135                                 doc.add(new Field("location",st.nextToken(),Field.Store.YES,
 136                                                 Field.Index.ANALYZED_NO_NORMS));
 137                                 doc.add(new Field("salary",st.nextToken(),Field.Store.YES,
 138                                                 Field.Index.ANALYZED_NO_NORMS));
 139                                 doc.add(new Field("type",st.nextToken(),Field.Store.YES,
 140                                                 Field.Index.ANALYZED_NO_NORMS));
 141                                 doc.add(new Field("description",st.nextToken(),Field.Store.YES,
 142                                                 Field.Index.ANALYZED));
 143                                 writer.addDocument(doc);
 144                         }
 145                         line=br.readLine();
 146                 }
 147                 writer.close();
 148
 149                 //open searcher
 150                 searcher=new IndexSearcher(rd, true);
 151         }
 152 }